TITLE: GCN CIRCULAR
NUMBER: 23896
SUBJECT: GRB190211A: GROWTH-India detection of optical afterglow
DATE: 19/02/15 01:45:15 GMT
FROM: Varun Bhalerao at Indian Inst of Tech
Harsh Kumar (IITB), Viraj karambelkar (IITB), Gaurav Waratkar(IITB), Shubham Srivastav (IITB), Tsewang Stanzin (IAO, IIAP), Varun Bhalerao (IITB), G.C. Anupama (IIAP) report on behalf of the GROWTH-India collaboration:
We observed the optical afterglow of GRB190211A (Marshall et al., GCN 23883; Xu et al. GCN 23884; Hu et al., GCN 23886; Stamatikos et al., GCN 23887; Evans et al., GCN 23888; K.E. Heintz et al., GCN 23890; M. Oeda et al.,GCN 23891; Gregory S.H.P. et al., GCN 23893) with the 0.7m robotic GROWTH-India telescope at the Indian Astronomical Observatory. We obtained 600 s exposures in two bands, starting at UT 2019-02-11 18:16:55.961 for r filter and at UT 2019-02-11 18:28:07.536 in i filter. The afterglow is clearly detected in both images. Magnitudes were calibrated using PanSTARRs reference stars in the same field. The measured magnitude in r filter image is 21.37+/- 0.2 and in i filter is 20.28+/- 0.3.
Based on our data combined with other r band measurements (Xu et al. GCN 23884; Hu et al., GCN 23886; M. Oeda et al.,GCN 23891; Heintz et al., GCN 23890), we see that the source flux is fading approximately as a power law t^-alpha, with alpha = 0.69 +/- 0.08.
GROWTH India telescope is a 70-cm telescope with a 0.7 degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).
[GCN OPS NOTE(14feb19): The GRB ID has been corrected by adding an "A".]